1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- A D A . C A L E N D A R --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 with Ada.Unchecked_Conversion;
34 with System.OS_Primitives;
36 package body Ada.Calendar is
38 --------------------------
39 -- Implementation Notes --
40 --------------------------
42 -- In complex algorithms, some variables of type Ada.Calendar.Time carry
43 -- suffix _S or _N to denote units of seconds or nanoseconds.
45 -- Because time is measured in different units and from different origins
46 -- on various targets, a system independent model is incorporated into
47 -- Ada.Calendar. The idea behind the design is to encapsulate all target
48 -- dependent machinery in a single package, thus providing a uniform
49 -- interface to all existing and any potential children.
51 -- package Ada.Calendar
52 -- procedure Split (5 parameters) -------+
53 -- | Call from local routine
55 -- package Formatting_Operations |
56 -- procedure Split (11 parameters) <--+
57 -- end Formatting_Operations |
60 -- package Ada.Calendar.Formatting | Call from child routine
61 -- procedure Split (9 or 10 parameters) -+
62 -- end Ada.Calendar.Formatting
64 -- The behaviour of the interfacing routines is controlled via various
65 -- flags. All new Ada 2005 types from children of Ada.Calendar are
66 -- emulated by a similar type. For instance, type Day_Number is replaced
67 -- by Integer in various routines. One ramification of this model is that
68 -- the caller site must perform validity checks on returned results.
69 -- The end result of this model is the lack of target specific files per
70 -- child of Ada.Calendar (a-calfor, a-calfor-vms, a-calfor-vxwors, etc).
72 -----------------------
73 -- Local Subprograms --
74 -----------------------
76 procedure Check_Within_Time_Bounds (T : Time_Rep);
77 -- Ensure that a time representation value falls withing the bounds of Ada
78 -- time. Leap seconds support is taken into account.
80 procedure Cumulative_Leap_Seconds
81 (Start_Date : Time_Rep;
83 Elapsed_Leaps : out Natural;
84 Next_Leap : out Time_Rep);
85 -- Elapsed_Leaps is the sum of the leap seconds that have occurred on or
86 -- after Start_Date and before (strictly before) End_Date. Next_Leap_Sec
87 -- represents the next leap second occurrence on or after End_Date. If
88 -- there are no leaps seconds after End_Date, End_Of_Time is returned.
89 -- End_Of_Time can be used as End_Date to count all the leap seconds that
90 -- have occurred on or after Start_Date.
92 -- Note: Any sub seconds of Start_Date and End_Date are discarded before
93 -- the calculations are done. For instance: if 113 seconds is a leap
94 -- second (it isn't) and 113.5 is input as an End_Date, the leap second
95 -- at 113 will not be counted in Leaps_Between, but it will be returned
96 -- as Next_Leap_Sec. Thus, if the caller wants to know if the End_Date is
97 -- a leap second, the comparison should be:
99 -- End_Date >= Next_Leap_Sec;
101 -- After_Last_Leap is designed so that this comparison works without
102 -- having to first check if Next_Leap_Sec is a valid leap second.
104 function Duration_To_Time_Rep is
105 new Ada.Unchecked_Conversion (Duration, Time_Rep);
106 -- Convert a duration value into a time representation value
108 function Time_Rep_To_Duration is
109 new Ada.Unchecked_Conversion (Time_Rep, Duration);
110 -- Convert a time representation value into a duration value
116 -- An integer time duration. The type is used whenever a positive elapsed
117 -- duration is needed, for instance when splitting a time value. Here is
118 -- how Time_Rep and Time_Dur are related:
120 -- 'First Ada_Low Ada_High 'Last
121 -- Time_Rep: +-------+------------------------+---------+
122 -- Time_Dur: +------------------------+---------+
125 type Time_Dur is range 0 .. 2 ** 63 - 1;
127 --------------------------
128 -- Leap seconds control --
129 --------------------------
132 pragma Import (C, Flag, "__gl_leap_seconds_support");
133 -- This imported value is used to determine whether the compilation had
134 -- binder flag "-y" present which enables leap seconds. A value of zero
135 -- signifies no leap seconds support while a value of one enables the
138 Leap_Support : constant Boolean := Flag = 1;
139 -- The above flag controls the usage of leap seconds in all Ada.Calendar
142 Leap_Seconds_Count : constant Natural := 23;
144 ---------------------
145 -- Local Constants --
146 ---------------------
148 Ada_Min_Year : constant Year_Number := Year_Number'First;
149 Secs_In_Four_Years : constant := (3 * 365 + 366) * Secs_In_Day;
150 Secs_In_Non_Leap_Year : constant := 365 * Secs_In_Day;
152 -- Lower and upper bound of Ada time. The zero (0) value of type Time is
153 -- positioned at year 2150. Note that the lower and upper bound account
154 -- for the non-leap centennial years.
156 Ada_Low : constant Time_Rep := -(61 * 366 + 188 * 365) * Nanos_In_Day;
157 Ada_High : constant Time_Rep := (60 * 366 + 190 * 365) * Nanos_In_Day;
159 -- Even though the upper bound of time is 2399-12-31 23:59:59.999999999
160 -- UTC, it must be increased to include all leap seconds.
162 Ada_High_And_Leaps : constant Time_Rep :=
163 Ada_High + Time_Rep (Leap_Seconds_Count) * Nano;
165 -- Two constants used in the calculations of elapsed leap seconds.
166 -- End_Of_Time is later than Ada_High in time zone -28. Start_Of_Time
167 -- is earlier than Ada_Low in time zone +28.
169 End_Of_Time : constant Time_Rep :=
170 Ada_High + Time_Rep (3) * Nanos_In_Day;
171 Start_Of_Time : constant Time_Rep :=
172 Ada_Low - Time_Rep (3) * Nanos_In_Day;
174 -- The Unix lower time bound expressed as nanoseconds since the
175 -- start of Ada time in UTC.
177 Unix_Min : constant Time_Rep :=
178 Ada_Low + Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day;
180 Cumulative_Days_Before_Month :
181 constant array (Month_Number) of Natural :=
182 (0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334);
184 -- The following table contains the hard time values of all existing leap
185 -- seconds. The values are produced by the utility program xleaps.adb.
187 Leap_Second_Times : constant array (1 .. Leap_Seconds_Count) of Time_Rep :=
188 (-5601484800000000000,
189 -5585587199000000000,
190 -5554051198000000000,
191 -5522515197000000000,
192 -5490979196000000000,
193 -5459356795000000000,
194 -5427820794000000000,
195 -5396284793000000000,
196 -5364748792000000000,
197 -5317487991000000000,
198 -5285951990000000000,
199 -5254415989000000000,
200 -5191257588000000000,
201 -5112287987000000000,
202 -5049129586000000000,
203 -5017593585000000000,
204 -4970332784000000000,
205 -4938796783000000000,
206 -4907260782000000000,
207 -4859827181000000000,
208 -4812566380000000000,
209 -4765132779000000000,
210 -4544207978000000000);
216 function "+" (Left : Time; Right : Duration) return Time is
217 pragma Unsuppress (Overflow_Check);
218 Left_N : constant Time_Rep := Time_Rep (Left);
220 return Time (Left_N + Duration_To_Time_Rep (Right));
222 when Constraint_Error =>
226 function "+" (Left : Duration; Right : Time) return Time is
235 function "-" (Left : Time; Right : Duration) return Time is
236 pragma Unsuppress (Overflow_Check);
237 Left_N : constant Time_Rep := Time_Rep (Left);
239 return Time (Left_N - Duration_To_Time_Rep (Right));
241 when Constraint_Error =>
245 function "-" (Left : Time; Right : Time) return Duration is
246 pragma Unsuppress (Overflow_Check);
248 -- The bounds of type Duration expressed as time representations
250 Dur_Low : constant Time_Rep := Duration_To_Time_Rep (Duration'First);
251 Dur_High : constant Time_Rep := Duration_To_Time_Rep (Duration'Last);
256 Res_N := Time_Rep (Left) - Time_Rep (Right);
258 -- Due to the extended range of Ada time, "-" is capable of producing
259 -- results which may exceed the range of Duration. In order to prevent
260 -- the generation of bogus values by the Unchecked_Conversion, we apply
261 -- the following check.
264 or else Res_N > Dur_High
269 return Time_Rep_To_Duration (Res_N);
271 when Constraint_Error =>
279 function "<" (Left, Right : Time) return Boolean is
281 return Time_Rep (Left) < Time_Rep (Right);
288 function "<=" (Left, Right : Time) return Boolean is
290 return Time_Rep (Left) <= Time_Rep (Right);
297 function ">" (Left, Right : Time) return Boolean is
299 return Time_Rep (Left) > Time_Rep (Right);
306 function ">=" (Left, Right : Time) return Boolean is
308 return Time_Rep (Left) >= Time_Rep (Right);
311 ------------------------------
312 -- Check_Within_Time_Bounds --
313 ------------------------------
315 procedure Check_Within_Time_Bounds (T : Time_Rep) is
318 if T < Ada_Low or else T > Ada_High_And_Leaps then
322 if T < Ada_Low or else T > Ada_High then
326 end Check_Within_Time_Bounds;
332 function Clock return Time is
333 Elapsed_Leaps : Natural;
334 Next_Leap_N : Time_Rep;
336 -- The system clock returns the time in UTC since the Unix Epoch of
337 -- 1970-01-01 00:00:00.0. We perform an origin shift to the Ada Epoch
338 -- by adding the number of nanoseconds between the two origins.
341 Duration_To_Time_Rep (System.OS_Primitives.Clock) +
345 -- If the target supports leap seconds, determine the number of leap
346 -- seconds elapsed until this moment.
349 Cumulative_Leap_Seconds
350 (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
352 -- The system clock may fall exactly on a leap second
354 if Res_N >= Next_Leap_N then
355 Elapsed_Leaps := Elapsed_Leaps + 1;
358 -- The target does not support leap seconds
364 Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano;
369 -----------------------------
370 -- Cumulative_Leap_Seconds --
371 -----------------------------
373 procedure Cumulative_Leap_Seconds
374 (Start_Date : Time_Rep;
376 Elapsed_Leaps : out Natural;
377 Next_Leap : out Time_Rep)
379 End_Index : Positive;
380 End_T : Time_Rep := End_Date;
381 Start_Index : Positive;
382 Start_T : Time_Rep := Start_Date;
385 -- Both input dates must be normalized to UTC
387 pragma Assert (Leap_Support and then End_Date >= Start_Date);
389 Next_Leap := End_Of_Time;
391 -- Make sure that the end date does not exceed the upper bound
394 if End_Date > Ada_High then
398 -- Remove the sub seconds from both dates
400 Start_T := Start_T - (Start_T mod Nano);
401 End_T := End_T - (End_T mod Nano);
403 -- Some trivial cases:
404 -- Leap 1 . . . Leap N
405 -- ---+========+------+############+-------+========+-----
406 -- Start_T End_T Start_T End_T
408 if End_T < Leap_Second_Times (1) then
410 Next_Leap := Leap_Second_Times (1);
413 elsif Start_T > Leap_Second_Times (Leap_Seconds_Count) then
415 Next_Leap := End_Of_Time;
419 -- Perform the calculations only if the start date is within the leap
420 -- second occurrences table.
422 if Start_T <= Leap_Second_Times (Leap_Seconds_Count) then
425 -- +----+----+-- . . . --+-------+---+
426 -- | T1 | T2 | | N - 1 | N |
427 -- +----+----+-- . . . --+-------+---+
429 -- | Start_Index | End_Index
430 -- +-------------------+
433 -- The idea behind the algorithm is to iterate and find two
434 -- closest dates which are after Start_T and End_T. Their
435 -- corresponding index difference denotes the number of leap
440 exit when Leap_Second_Times (Start_Index) >= Start_T;
441 Start_Index := Start_Index + 1;
444 End_Index := Start_Index;
446 exit when End_Index > Leap_Seconds_Count
447 or else Leap_Second_Times (End_Index) >= End_T;
448 End_Index := End_Index + 1;
451 if End_Index <= Leap_Seconds_Count then
452 Next_Leap := Leap_Second_Times (End_Index);
455 Elapsed_Leaps := End_Index - Start_Index;
460 end Cumulative_Leap_Seconds;
466 function Day (Date : Time) return Day_Number is
471 pragma Unreferenced (Y, M, S);
473 Split (Date, Y, M, D, S);
481 function Is_Leap (Year : Year_Number) return Boolean is
483 -- Leap centennial years
485 if Year mod 400 = 0 then
488 -- Non-leap centennial years
490 elsif Year mod 100 = 0 then
496 return Year mod 4 = 0;
504 function Month (Date : Time) return Month_Number is
509 pragma Unreferenced (Y, D, S);
511 Split (Date, Y, M, D, S);
519 function Seconds (Date : Time) return Day_Duration is
524 pragma Unreferenced (Y, M, D);
526 Split (Date, Y, M, D, S);
536 Year : out Year_Number;
537 Month : out Month_Number;
538 Day : out Day_Number;
539 Seconds : out Day_Duration)
547 pragma Unreferenced (H, M, Se, Ss, Le);
550 -- Even though the input time zone is UTC (0), the flag Is_Ada_05 will
551 -- ensure that Split picks up the local time zone.
553 Formatting_Operations.Split
570 or else not Month'Valid
571 or else not Day'Valid
572 or else not Seconds'Valid
584 Month : Month_Number;
586 Seconds : Day_Duration := 0.0) return Time
588 -- The values in the following constants are irrelevant, they are just
589 -- placeholders; the choice of constructing a Day_Duration value is
590 -- controlled by the Use_Day_Secs flag.
592 H : constant Integer := 1;
593 M : constant Integer := 1;
594 Se : constant Integer := 1;
595 Ss : constant Duration := 0.1;
601 or else not Month'Valid
602 or else not Day'Valid
603 or else not Seconds'Valid
608 -- Even though the input time zone is UTC (0), the flag Is_Ada_05 will
609 -- ensure that Split picks up the local time zone.
612 Formatting_Operations.Time_Of
622 Use_Day_Secs => True,
631 function Year (Date : Time) return Year_Number is
636 pragma Unreferenced (M, D, S);
638 Split (Date, Y, M, D, S);
642 -- The following packages assume that Time is a signed 64 bit integer
643 -- type, the units are nanoseconds and the origin is the start of Ada
644 -- time (1901-01-01 00:00:00.0 UTC).
646 ---------------------------
647 -- Arithmetic_Operations --
648 ---------------------------
650 package body Arithmetic_Operations is
656 function Add (Date : Time; Days : Long_Integer) return Time is
657 pragma Unsuppress (Overflow_Check);
658 Date_N : constant Time_Rep := Time_Rep (Date);
660 return Time (Date_N + Time_Rep (Days) * Nanos_In_Day);
662 when Constraint_Error =>
673 Days : out Long_Integer;
674 Seconds : out Duration;
675 Leap_Seconds : out Integer)
679 Elapsed_Leaps : Natural;
681 Negate : Boolean := False;
682 Next_Leap_N : Time_Rep;
684 Sub_Secs_Diff : Time_Rep;
687 -- Both input time values are assumed to be in UTC
689 if Left >= Right then
690 Later := Time_Rep (Left);
691 Earlier := Time_Rep (Right);
693 Later := Time_Rep (Right);
694 Earlier := Time_Rep (Left);
698 -- If the target supports leap seconds, process them
701 Cumulative_Leap_Seconds
702 (Earlier, Later, Elapsed_Leaps, Next_Leap_N);
704 if Later >= Next_Leap_N then
705 Elapsed_Leaps := Elapsed_Leaps + 1;
708 -- The target does not support leap seconds
714 -- Sub seconds processing. We add the resulting difference to one
715 -- of the input dates in order to account for any potential rounding
716 -- of the difference in the next step.
718 Sub_Secs_Diff := Later mod Nano - Earlier mod Nano;
719 Earlier := Earlier + Sub_Secs_Diff;
720 Sub_Secs := Duration (Sub_Secs_Diff) / Nano_F;
722 -- Difference processing. This operation should be able to calculate
723 -- the difference between opposite values which are close to the end
724 -- and start of Ada time. To accommodate the large range, we convert
725 -- to seconds. This action may potentially round the two values and
726 -- either add or drop a second. We compensate for this issue in the
730 Time_Dur (Later / Nano - Earlier / Nano) - Time_Dur (Elapsed_Leaps);
732 Days := Long_Integer (Res_Dur / Secs_In_Day);
733 Seconds := Duration (Res_Dur mod Secs_In_Day) + Sub_Secs;
734 Leap_Seconds := Integer (Elapsed_Leaps);
740 if Leap_Seconds /= 0 then
741 Leap_Seconds := -Leap_Seconds;
750 function Subtract (Date : Time; Days : Long_Integer) return Time is
751 pragma Unsuppress (Overflow_Check);
752 Date_N : constant Time_Rep := Time_Rep (Date);
754 return Time (Date_N - Time_Rep (Days) * Nanos_In_Day);
756 when Constraint_Error =>
760 end Arithmetic_Operations;
762 ---------------------------
763 -- Conversion_Operations --
764 ---------------------------
766 package body Conversion_Operations is
768 Epoch_Offset : constant Time_Rep :=
769 (136 * 365 + 44 * 366) * Nanos_In_Day;
770 -- The difference between 2150-1-1 UTC and 1970-1-1 UTC expressed in
771 -- nanoseconds. Note that year 2100 is non-leap.
777 function To_Ada_Time (Unix_Time : Long_Integer) return Time is
778 pragma Unsuppress (Overflow_Check);
779 Unix_Rep : constant Time_Rep := Time_Rep (Unix_Time) * Nano;
781 return Time (Unix_Rep - Epoch_Offset);
783 when Constraint_Error =>
798 tm_isdst : Integer) return Time
800 pragma Unsuppress (Overflow_Check);
802 Month : Month_Number;
811 Year := Year_Number (1900 + tm_year);
812 Month := Month_Number (1 + tm_mon);
813 Day := Day_Number (tm_day);
815 -- Step 1: Validity checks of input values
818 or else not Month'Valid
819 or else not Day'Valid
820 or else tm_hour not in 0 .. 24
821 or else tm_min not in 0 .. 59
822 or else tm_sec not in 0 .. 60
823 or else tm_isdst not in -1 .. 1
828 -- Step 2: Potential leap second
838 -- Step 3: Calculate the time value
842 (Formatting_Operations.Time_Of
846 Day_Secs => 0.0, -- Time is given in h:m:s
850 Sub_Sec => 0.0, -- No precise sub second given
852 Use_Day_Secs => False, -- Time is given in h:m:s
853 Is_Ada_05 => True, -- Force usage of explicit time zone
854 Time_Zone => 0)); -- Place the value in UTC
856 -- Step 4: Daylight Savings Time
859 Result := Result + Time_Rep (3_600) * Nano;
862 return Time (Result);
865 when Constraint_Error =>
874 (tv_sec : Long_Integer;
875 tv_nsec : Long_Integer) return Duration
877 pragma Unsuppress (Overflow_Check);
879 return Duration (tv_sec) + Duration (tv_nsec) / Nano_F;
882 ------------------------
883 -- To_Struct_Timespec --
884 ------------------------
886 procedure To_Struct_Timespec
888 tv_sec : out Long_Integer;
889 tv_nsec : out Long_Integer)
891 pragma Unsuppress (Overflow_Check);
893 Nano_Secs : Duration;
896 -- Seconds extraction, avoid potential rounding errors
899 tv_sec := Long_Integer (Secs);
901 -- Nanoseconds extraction
903 Nano_Secs := D - Duration (tv_sec);
904 tv_nsec := Long_Integer (Nano_Secs * Nano);
905 end To_Struct_Timespec;
911 procedure To_Struct_Tm
913 tm_year : out Integer;
914 tm_mon : out Integer;
915 tm_day : out Integer;
916 tm_hour : out Integer;
917 tm_min : out Integer;
918 tm_sec : out Integer)
920 pragma Unsuppress (Overflow_Check);
922 Month : Month_Number;
924 Day_Secs : Day_Duration;
929 -- Step 1: Split the input time
931 Formatting_Operations.Split
932 (T, Year, Month, tm_day, Day_Secs,
933 tm_hour, tm_min, Second, Sub_Sec, Leap_Sec, True, 0);
935 -- Step 2: Correct the year and month
937 tm_year := Year - 1900;
940 -- Step 3: Handle leap second occurrences
953 function To_Unix_Time (Ada_Time : Time) return Long_Integer is
954 pragma Unsuppress (Overflow_Check);
955 Ada_Rep : constant Time_Rep := Time_Rep (Ada_Time);
957 return Long_Integer ((Ada_Rep + Epoch_Offset) / Nano);
959 when Constraint_Error =>
962 end Conversion_Operations;
964 ----------------------
965 -- Delay_Operations --
966 ----------------------
968 package body Delay_Operations is
974 function To_Duration (Date : Time) return Duration is
975 Elapsed_Leaps : Natural;
976 Next_Leap_N : Time_Rep;
980 Res_N := Time_Rep (Date);
982 -- If the target supports leap seconds, remove any leap seconds
983 -- elapsed up to the input date.
986 Cumulative_Leap_Seconds
987 (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
989 -- The input time value may fall on a leap second occurrence
991 if Res_N >= Next_Leap_N then
992 Elapsed_Leaps := Elapsed_Leaps + 1;
995 -- The target does not support leap seconds
1001 Res_N := Res_N - Time_Rep (Elapsed_Leaps) * Nano;
1003 -- Perform a shift in origins, note that enforcing type Time on
1004 -- both operands will invoke Ada.Calendar."-".
1006 return Time (Res_N) - Time (Unix_Min);
1009 end Delay_Operations;
1011 ---------------------------
1012 -- Formatting_Operations --
1013 ---------------------------
1015 package body Formatting_Operations is
1021 function Day_Of_Week (Date : Time) return Integer is
1032 pragma Unreferenced (Ds, H, Mi, Se, Su, Le);
1034 Day_Count : Long_Integer;
1039 Formatting_Operations.Split
1053 -- Build a time value in the middle of the same day
1057 (Formatting_Operations.Time_Of
1067 Use_Day_Secs => False,
1071 -- Determine the elapsed seconds since the start of Ada time
1073 Res_Dur := Time_Dur (Res_N / Nano - Ada_Low / Nano);
1075 -- Count the number of days since the start of Ada time. 1901-1-1
1076 -- GMT was a Tuesday.
1078 Day_Count := Long_Integer (Res_Dur / Secs_In_Day) + 1;
1080 return Integer (Day_Count mod 7);
1089 Year : out Year_Number;
1090 Month : out Month_Number;
1091 Day : out Day_Number;
1092 Day_Secs : out Day_Duration;
1094 Minute : out Integer;
1095 Second : out Integer;
1096 Sub_Sec : out Duration;
1097 Leap_Sec : out Boolean;
1098 Is_Ada_05 : Boolean;
1099 Time_Zone : Long_Integer)
1101 -- The following constants represent the number of nanoseconds
1102 -- elapsed since the start of Ada time to and including the non
1103 -- leap centennial years.
1105 Year_2101 : constant Time_Rep := Ada_Low +
1106 Time_Rep (49 * 366 + 151 * 365) * Nanos_In_Day;
1107 Year_2201 : constant Time_Rep := Ada_Low +
1108 Time_Rep (73 * 366 + 227 * 365) * Nanos_In_Day;
1109 Year_2301 : constant Time_Rep := Ada_Low +
1110 Time_Rep (97 * 366 + 303 * 365) * Nanos_In_Day;
1112 Date_Dur : Time_Dur;
1114 Day_Seconds : Natural;
1115 Elapsed_Leaps : Natural;
1116 Four_Year_Segs : Natural;
1117 Hour_Seconds : Natural;
1118 Is_Leap_Year : Boolean;
1119 Next_Leap_N : Time_Rep;
1120 Rem_Years : Natural;
1121 Sub_Sec_N : Time_Rep;
1125 Date_N := Time_Rep (Date);
1127 -- Step 1: Leap seconds processing in UTC
1129 if Leap_Support then
1130 Cumulative_Leap_Seconds
1131 (Start_Of_Time, Date_N, Elapsed_Leaps, Next_Leap_N);
1133 Leap_Sec := Date_N >= Next_Leap_N;
1136 Elapsed_Leaps := Elapsed_Leaps + 1;
1139 -- The target does not support leap seconds
1146 Date_N := Date_N - Time_Rep (Elapsed_Leaps) * Nano;
1148 -- Step 2: Time zone processing. This action converts the input date
1149 -- from GMT to the requested time zone.
1152 if Time_Zone /= 0 then
1153 Date_N := Date_N + Time_Rep (Time_Zone) * 60 * Nano;
1160 Off : constant Long_Integer :=
1161 Time_Zones_Operations.UTC_Time_Offset (Time (Date_N));
1163 Date_N := Date_N + Time_Rep (Off) * Nano;
1167 -- Step 3: Non-leap centennial year adjustment in local time zone
1169 -- In order for all divisions to work properly and to avoid more
1170 -- complicated arithmetic, we add fake February 29s to dates which
1171 -- occur after a non-leap centennial year.
1173 if Date_N >= Year_2301 then
1174 Date_N := Date_N + Time_Rep (3) * Nanos_In_Day;
1176 elsif Date_N >= Year_2201 then
1177 Date_N := Date_N + Time_Rep (2) * Nanos_In_Day;
1179 elsif Date_N >= Year_2101 then
1180 Date_N := Date_N + Time_Rep (1) * Nanos_In_Day;
1183 -- Step 4: Sub second processing in local time zone
1185 Sub_Sec_N := Date_N mod Nano;
1186 Sub_Sec := Duration (Sub_Sec_N) / Nano_F;
1187 Date_N := Date_N - Sub_Sec_N;
1189 -- Convert Date_N into a time duration value, changing the units
1192 Date_Dur := Time_Dur (Date_N / Nano - Ada_Low / Nano);
1194 -- Step 5: Year processing in local time zone. Determine the number
1195 -- of four year segments since the start of Ada time and the input
1198 Four_Year_Segs := Natural (Date_Dur / Secs_In_Four_Years);
1200 if Four_Year_Segs > 0 then
1201 Date_Dur := Date_Dur - Time_Dur (Four_Year_Segs) *
1205 -- Calculate the remaining non-leap years
1207 Rem_Years := Natural (Date_Dur / Secs_In_Non_Leap_Year);
1209 if Rem_Years > 3 then
1213 Date_Dur := Date_Dur - Time_Dur (Rem_Years) * Secs_In_Non_Leap_Year;
1215 Year := Ada_Min_Year + Natural (4 * Four_Year_Segs + Rem_Years);
1216 Is_Leap_Year := Is_Leap (Year);
1218 -- Step 6: Month and day processing in local time zone
1220 Year_Day := Natural (Date_Dur / Secs_In_Day) + 1;
1224 -- Processing for months after January
1226 if Year_Day > 31 then
1228 Year_Day := Year_Day - 31;
1230 -- Processing for a new month or a leap February
1233 and then (not Is_Leap_Year or else Year_Day > 29)
1236 Year_Day := Year_Day - 28;
1238 if Is_Leap_Year then
1239 Year_Day := Year_Day - 1;
1244 while Year_Day > Days_In_Month (Month) loop
1245 Year_Day := Year_Day - Days_In_Month (Month);
1251 -- Step 7: Hour, minute, second and sub second processing in local
1254 Day := Day_Number (Year_Day);
1255 Day_Seconds := Integer (Date_Dur mod Secs_In_Day);
1256 Day_Secs := Duration (Day_Seconds) + Sub_Sec;
1257 Hour := Day_Seconds / 3_600;
1258 Hour_Seconds := Day_Seconds mod 3_600;
1259 Minute := Hour_Seconds / 60;
1260 Second := Hour_Seconds mod 60;
1268 (Year : Year_Number;
1269 Month : Month_Number;
1271 Day_Secs : Day_Duration;
1276 Leap_Sec : Boolean := False;
1277 Use_Day_Secs : Boolean := False;
1278 Is_Ada_05 : Boolean := False;
1279 Time_Zone : Long_Integer := 0) return Time
1282 Elapsed_Leaps : Natural;
1283 Next_Leap_N : Time_Rep;
1285 Rounded_Res_N : Time_Rep;
1288 -- Step 1: Check whether the day, month and year form a valid date
1290 if Day > Days_In_Month (Month)
1291 and then (Day /= 29 or else Month /= 2 or else not Is_Leap (Year))
1296 -- Start accumulating nanoseconds from the low bound of Ada time
1300 -- Step 2: Year processing and centennial year adjustment. Determine
1301 -- the number of four year segments since the start of Ada time and
1304 Count := (Year - Year_Number'First) / 4;
1305 Res_N := Res_N + Time_Rep (Count) * Secs_In_Four_Years * Nano;
1307 -- Note that non-leap centennial years are automatically considered
1308 -- leap in the operation above. An adjustment of several days is
1309 -- required to compensate for this.
1312 Res_N := Res_N - Time_Rep (3) * Nanos_In_Day;
1314 elsif Year > 2200 then
1315 Res_N := Res_N - Time_Rep (2) * Nanos_In_Day;
1317 elsif Year > 2100 then
1318 Res_N := Res_N - Time_Rep (1) * Nanos_In_Day;
1321 -- Add the remaining non-leap years
1323 Count := (Year - Year_Number'First) mod 4;
1324 Res_N := Res_N + Time_Rep (Count) * Secs_In_Non_Leap_Year * Nano;
1326 -- Step 3: Day of month processing. Determine the number of days
1327 -- since the start of the current year. Do not add the current
1328 -- day since it has not elapsed yet.
1330 Count := Cumulative_Days_Before_Month (Month) + Day - 1;
1332 -- The input year is leap and we have passed February
1340 Res_N := Res_N + Time_Rep (Count) * Nanos_In_Day;
1342 -- Step 4: Hour, minute, second and sub second processing
1344 if Use_Day_Secs then
1345 Res_N := Res_N + Duration_To_Time_Rep (Day_Secs);
1349 Time_Rep (Hour * 3_600 + Minute * 60 + Second) * Nano;
1351 if Sub_Sec = 1.0 then
1352 Res_N := Res_N + Time_Rep (1) * Nano;
1354 Res_N := Res_N + Duration_To_Time_Rep (Sub_Sec);
1358 -- At this point, the generated time value should be withing the
1359 -- bounds of Ada time.
1361 Check_Within_Time_Bounds (Res_N);
1363 -- Step 4: Time zone processing. At this point we have built an
1364 -- arbitrary time value which is not related to any time zone.
1365 -- For simplicity, the time value is normalized to GMT, producing
1366 -- a uniform representation which can be treated by arithmetic
1367 -- operations for instance without any additional corrections.
1370 if Time_Zone /= 0 then
1371 Res_N := Res_N - Time_Rep (Time_Zone) * 60 * Nano;
1378 Current_Off : constant Long_Integer :=
1379 Time_Zones_Operations.UTC_Time_Offset
1381 Current_Res_N : constant Time_Rep :=
1382 Res_N - Time_Rep (Current_Off) * Nano;
1383 Off : constant Long_Integer :=
1384 Time_Zones_Operations.UTC_Time_Offset
1385 (Time (Current_Res_N));
1387 Res_N := Res_N - Time_Rep (Off) * Nano;
1391 -- Step 5: Leap seconds processing in GMT
1393 if Leap_Support then
1394 Cumulative_Leap_Seconds
1395 (Start_Of_Time, Res_N, Elapsed_Leaps, Next_Leap_N);
1397 Res_N := Res_N + Time_Rep (Elapsed_Leaps) * Nano;
1399 -- An Ada 2005 caller requesting an explicit leap second or an
1400 -- Ada 95 caller accounting for an invisible leap second.
1403 or else Res_N >= Next_Leap_N
1405 Res_N := Res_N + Time_Rep (1) * Nano;
1408 -- Leap second validity check
1410 Rounded_Res_N := Res_N - (Res_N mod Nano);
1414 and then Rounded_Res_N /= Next_Leap_N
1420 return Time (Res_N);
1423 end Formatting_Operations;
1425 ---------------------------
1426 -- Time_Zones_Operations --
1427 ---------------------------
1429 package body Time_Zones_Operations is
1431 -- The Unix time bounds in nanoseconds: 1970/1/1 .. 2037/1/1
1433 Unix_Min : constant Time_Rep := Ada_Low +
1434 Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day;
1436 Unix_Max : constant Time_Rep := Ada_Low +
1437 Time_Rep (34 * 366 + 102 * 365) * Nanos_In_Day +
1438 Time_Rep (Leap_Seconds_Count) * Nano;
1440 -- The following constants denote February 28 during non-leap
1441 -- centennial years, the units are nanoseconds.
1443 T_2100_2_28 : constant Time_Rep := Ada_Low +
1444 (Time_Rep (49 * 366 + 150 * 365 + 59) * Secs_In_Day +
1445 Time_Rep (Leap_Seconds_Count)) * Nano;
1447 T_2200_2_28 : constant Time_Rep := Ada_Low +
1448 (Time_Rep (73 * 366 + 226 * 365 + 59) * Secs_In_Day +
1449 Time_Rep (Leap_Seconds_Count)) * Nano;
1451 T_2300_2_28 : constant Time_Rep := Ada_Low +
1452 (Time_Rep (97 * 366 + 302 * 365 + 59) * Secs_In_Day +
1453 Time_Rep (Leap_Seconds_Count)) * Nano;
1455 -- 56 years (14 leap years + 42 non leap years) in nanoseconds:
1457 Nanos_In_56_Years : constant := (14 * 366 + 42 * 365) * Nanos_In_Day;
1459 -- Base C types. There is no point dragging in Interfaces.C just for
1460 -- these four types.
1462 type char_Pointer is access Character;
1463 subtype int is Integer;
1464 subtype long is Long_Integer;
1465 type long_Pointer is access all long;
1467 -- The Ada equivalent of struct tm and type time_t
1470 tm_sec : int; -- seconds after the minute (0 .. 60)
1471 tm_min : int; -- minutes after the hour (0 .. 59)
1472 tm_hour : int; -- hours since midnight (0 .. 24)
1473 tm_mday : int; -- day of the month (1 .. 31)
1474 tm_mon : int; -- months since January (0 .. 11)
1475 tm_year : int; -- years since 1900
1476 tm_wday : int; -- days since Sunday (0 .. 6)
1477 tm_yday : int; -- days since January 1 (0 .. 365)
1478 tm_isdst : int; -- Daylight Savings Time flag (-1 .. 1)
1479 tm_gmtoff : long; -- offset from UTC in seconds
1480 tm_zone : char_Pointer; -- timezone abbreviation
1483 type tm_Pointer is access all tm;
1485 subtype time_t is long;
1486 type time_t_Pointer is access all time_t;
1488 procedure localtime_tzoff
1489 (C : time_t_Pointer;
1491 off : long_Pointer);
1492 pragma Import (C, localtime_tzoff, "__gnat_localtime_tzoff");
1493 -- This is a lightweight wrapper around the system library function
1494 -- localtime_r. Parameter 'off' captures the UTC offset which is either
1495 -- retrieved from the tm struct or calculated from the 'timezone' extern
1496 -- and the tm_isdst flag in the tm struct.
1498 ---------------------
1499 -- UTC_Time_Offset --
1500 ---------------------
1502 function UTC_Time_Offset (Date : Time) return Long_Integer is
1503 Adj_Cent : Integer := 0;
1505 Offset : aliased long;
1506 Secs_T : aliased time_t;
1507 Secs_TM : aliased tm;
1510 Date_N := Time_Rep (Date);
1512 -- Dates which are 56 years apart fall on the same day, day light
1513 -- saving and so on. Non-leap centennial years violate this rule by
1514 -- one day and as a consequence, special adjustment is needed.
1516 if Date_N > T_2100_2_28 then
1517 if Date_N > T_2200_2_28 then
1518 if Date_N > T_2300_2_28 then
1529 if Adj_Cent > 0 then
1530 Date_N := Date_N - Time_Rep (Adj_Cent) * Nanos_In_Day;
1533 -- Shift the date within bounds of Unix time
1535 while Date_N < Unix_Min loop
1536 Date_N := Date_N + Nanos_In_56_Years;
1539 while Date_N >= Unix_Max loop
1540 Date_N := Date_N - Nanos_In_56_Years;
1543 -- Perform a shift in origins from Ada to Unix
1545 Date_N := Date_N - Unix_Min;
1547 -- Convert the date into seconds
1549 Secs_T := time_t (Date_N / Nano);
1552 (Secs_T'Unchecked_Access,
1553 Secs_TM'Unchecked_Access,
1554 Offset'Unchecked_Access);
1557 end UTC_Time_Offset;
1559 end Time_Zones_Operations;
1561 -- Start of elaboration code for Ada.Calendar
1564 System.OS_Primitives.Initialize;